Improvement in gas



2 Sheets--Sheet l.

Patented Aug. 3,1375.

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J'. C. MITCHELL.

Gas-Generator.

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WITNESSES 2 Sheets--Sheet 2.

J. G. MITCHELL.

Gas-Generator.

Patented Aug. 3,1875.

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ou 2:72 sworl Improved Gas-Generator;

UNITED STATES PATENT OEEIcE JAMES C. MITCHELL, OF LANCASTER, NEWHAMPSHIRE.

-IMPROVEMENT IN GASWGENERATORS.

Specication forming part of Letters Patent No.166,288, dated August 3,1875 application filed May 28, 1875.

To all whom it may concern:

Be it known that I, JAMEs C. MITCHELL, of Lancaster, in the county ofGoos and State of New Hampshire, have invented a new and and do herebydeclare that the following is a full, clear, and exact description ofthe same, reference being had to the accompanying drawing, forming apart of this specication, in which- Figure l is a Vertical frontelevation; Fig. 2, a detail of the air-tight furnace-door; Fig. 3, asectional side elevation; Fig. 4, a sectional detail of one of thepurilers.

This invention relates to certain improve- A ments in the manufacture ofilluminating-gas,

designed to utilize any kind of fuel for the production of the gas, andapplicable to limited manufacture, as for private families, &c. Itconsists in a retort placed within a furnace, or a common stove, ifdesired, and having an air-tight door of peculiar construction, and

a communication direct with the furnace, by means of which constructionthe gaseous contents of the retort may be drawninto the furnace andburned when the air-tight door is to be opened for drawing andrecharging the retprt. It also consists in the peculiar construction andarrangement of the tops ofthe purifiersand an air-tight door to theretort, and the combination with the feedpipe to the gas-holder of aball-valve to prevent back pressure, as `hereinafter more fullydescribed.

In the drawing, A represents the retort, which is made of cast-iron orother suitable ,materiah and contains the wood, coal, fats,

or other material from which the gas is to be made. The front of saidretort is made perfectly smooth, and is provided with an airtight door,P, which also has a smooth face. The said door is provided with a latch,a, anda spring, b, and the retort has a catch, c, the front side of saidcatch, against which the latch binds to prevent the opening of the door,being made inclined inwardly from the bottom to the top, so that whenthe spring forces up the latch the latter engages thesaid incline tohold the door tightly to the face of the retort. V is a pipe, having alstop-cock, C, which leads from the retort A directly into the furnaceB. Whenever the retort is to be recharged, or opened for any causewhatever,

the stop-cock Gis turned. The gaseous contents of the retort then pass,and the draft ofthe furnace, directly into the latter, and are consumed,and the door P of the retort may then be opened, the back pressure ofgas from the holder and condenser being prevented byvalves andstop-cock. E is the outlet-pipe from the retort for the gas. rIhis pipepasses all around the retort in the furnace to insure the thoroughdecomposition of the undecomposed products of distillation, andcommunicates through a stop-cock, C1,

with` the condenser G. The latterI vessel has,

near its bottom astop-cock, C2, through which the distilled andcondensed liquids are drawn off, and has a pipe, F, that passes the gasthrough the cooler H to the purifiers, which said cooler consists simplyof a tank or trough filled with water and prov-ided with a suitableoutlet. As the gas passes from the said cooler it enters one of twopurifiers, I I, which are of a similar construction. These purifiersconsist of upright chambers, having vats Xin the bottom, and detachabletables S S1 S2, resting one above the other, which are constructed ofmetal, with perforated tops, upon each of which lime is placed, andthrough which said perforations the gas passes, going up through onepurifier and down the other. R is a de tachable connecting-pipe, whichconducts the gas from one puriterto the other, and terminates at eachend in a downwardly-opening detachable cover, J, for the purifiers,which rests in a trough, O, at the top of said purifiers,- which is lledwith water, the connection between the two purifiers being thus awatersealed detachable one, so that the purifiers maybe readilyinspected and the lime renewed whenever desirable. K is a pipeleadingfrom one of the purifiers to the gas-holder J, which consists inthe usual tank filled with water, and an inverted cylindrical vesselresting therein and movingn guideways. Nisaballvalve, which rests in thetop of pipe K, and which,"`while it allows the passage of the gas to theholder, prevents the back pressure. L

is the pipe that feeds the gas from the holder" to the burners.

With respect to my method'of disposing of the contents of thegas-retort, I am awareof the fact that the outpouring gases from the byexpansion Opened retort-door have been gathered into an overhanging hoodand conductedthrough a pipe into the furnace; but in this case the gasescome inio contact withthe air and produce an explosive compound, Which,being ignited in the furnace, is liable to strike back and result in anexplosion, and consequent injury to the Workmen. Itherefore limit myinvention to the terms of the ciaim, in which the gas is conducteddirectly to the furnace Without admixture of air, and before the openingof the retort-door. l

Having thus described my invention, What I claim as new is- 1. Thecombination, With retort B, havin g a smooth face, of a door, P, havingacorresponding smooth face, the latch a, spring b, and catch c, for thepurpose of maintaining the door closed with an air-tight connection,substantiaily as described.

2. The combination, with the purifiers I I', having Water-troughs O, ofthe detachable tube R and the covers T, as and for the purpose setforth.

3. The combination, in a gaslgenerator, with the pipe K, terminating inthe gas-holder, of a ball-valve, N, resting in the end of said pipe, forthe purpose of preventing back pressure, as described.

4. The method of freeing air-tight gasi

